In September 2004, DFM Engineering was awarded a contract to provide a gimbal to a laboratory of the US
Department of Energy.

The gimbal will support instruments developed by the laboratory for performing various field measurements.

The gimbal is an Altitude over Azimuth (Alt-Az) computer driven two axes mount and provides an instrument
mounting plate with standard optical table bolt patterns.

One of the primary concerns of the customer was ease of use and programming.

While the gimbal control system is very similar to those used by DFM Engineering LIDAR
scanners, a users interface and command program was provided which communicates with the gimbal
control software.

The source code for the user interface command program allows the customer to easily write their
own command program incorporating any special features they need.

The command program may be used to perform powerful motions including a user defined raster scan.

The word 'Gimbal' is fairly generic
and can refer to any configuration of a support that moves in typically two axes. The most common
configuration is an altitude over azimuth system where the azimuth axis is attached to the earth
(or fixed reference plane).

Gimbal Configurations Summary

Alt-Az:

This configuration consists of a structure where the azimuth axis is attached to the fixed
reference point and the altitude (or elevation) axis is attached to the rotating part
of the azimuth structure.

One rotation is about a vertical line (an azimuth rotation) and the second motion is about
a horizontal line (the elevation rotation).

This configuration is used for surveying, landscape camera mounts, gun mounts, and is the
typical way a person uses their eyes to look at terrestrial scenes.

Alt-Alt:

This configuration consists of a structure that rotates about a horizontal axis sometimes
called the "X" or "Major"
axis and, attached to the major axis, is another rotation stage whose axis of rotation
is perpendicular to the major axis.

This axis is sometimes called the "Y"
axis or "Minor" axis. Usually the axes are located North-South (for the major
axis) and East-West (for the minor axis), but the azimuth alignment can be at any position.
Rotation in either axis moves the payload in an up-down motion.

The typical use for the Alt-Alt configuration is for tracking artificial satellites.

Equatorial:

This configuration is a special alignment case of the previous gimbals where the major
(or azimuth) axis is inclined at an angle from the horizontal equal to the site latitude
and the azimuth alignment is true North.

This configuration places the major axis of rotation parallel to the rotation axis of the
earth.

The typical use for the equatorial configuration is for astronomical telescopes because
a simple rotation about the "major" axis (called the "polar" axis)
counteracts the earth's rotation.

Examining the three configurations leads to the conclusion that they are really
the same. Only the orientation of the gimbal referred to the fixed mounting surface (typically
the earth's surface) is different.

DFM Engineering, Inc. designed and manufactured the Model
GIM-1-120 for the Department of Energy Laboratory. The table below describes the DFM standard gimbal
features and includes the specific features requested by the US
Department of Energy.